这是模拟器中iOS 8.0中的已知错误。目前唯一的解决方法是使用defaults命令行工具从命令行设置首选项。

This is a known bug in iOS 8.0 in the simulator. The only workaround at this time is to set the preferences from the command line using the defaults command line tool.

defaults write ˜/Library/Developer/CoreSimulator/Devices/<UDID>/data/Containers/Data/Application/<App UUID>/Library/Preferences/...

您还需要找到相关的UDID。

You also need to find the relevant UDID.